Fluid dispensing system

Abstract

An electronically controlled, pneumatically actuated pumping system is provided that is especially designed for the precision dispensing of liquids. The system includes a positively actuated inlet valve, and a small-diameter, long-stroke pumping piston that is physically stopped at each end of its stroke. The unique inlet valve and piston enable the system to repetitively dispense metered volumes of fluid at better than one tenth of one percent accuracy. A unique calibration mechanism and detachable dispensing head allow for the rapid disassembly, cleaning, and reassembly of the system. An alternative embodiment of the pumping system incorporates a plurality of dispensing nozzles controlled by a single inlet valve and pumping piston combination. The dispensing unit may be shiftably mounted on a vertically oriented stand, and may be automatically shifted upwardly as fluid is dispensed to minimize splashing and atomizing of the dispensed fluid.

I claim: 
     
       1. In a fluid dispensing system having a main body defining an internal cylinder cavity and a piston having a variable stroke length shiftably carried within said cylinder cavity for dispensing fluid from said system in metered amounts, the improvement comprising: calibration means detachably, operably coupled to said body for limiting said stroke length of said piston and thereby controlling the amount of said fluid dispensed from said system, said calibration means including structure within said main body defining a calibration means receiving channel communicating with said cylinder cavity, said channel presenting a channel sidewall and defining a channel diameter;   a first calibration member operably, detachably coupled with said body in exact, predetermined spacial relationship with said body, said first calibration member including structure defining an internally threaded bore communicating with said channel;   a second calibration member comprising a rod having an externally threaded portion complementarily, shiftably carried within said first calibration member internally threaded bore, and an end fitting receiving portion extending into said channel and defining a rod end fitting portion largest diameter; and   an end fitting comprising a piston abutment portion, and a sleeve portion shiftably received within said channel and shiftably carried by said second calibration member end fitting portion, said sleeve portion including sealing means for creating a fluid tight seal between said sleeve portion and said channel sidewall, said sleeve portion further having structure defining an internal, rod receiving slot, said slot having an inner diameter no smaller than said rod end fitting portion largest diameter, whereby said end fitting may be slidably removed from said rod end fitting portion such that said first and second calibration members may be attached and detached from said body while said end fitting remains within said calibration means receiving channel.     
     
     
       2. The invention as claimed in claim 1, said end fitting piston abutment portion including a radially extending flange carried within said cylinder cavity, said flange having a diameter larger than said channel diameter whereby said flange retains said end fitting within said body when said first and second calibration means are detached from said body. 
     
     
       3. The improvement as claimed in claim 1, including means operably coupled to said first and second calibration members for selectively locking said second calibration member in relative position to said first calibration member. 
     
     
       4. In a fluid dispensing system having a main body defining an internal cylinder cavity and a piston having a variable stroke length shiftably carried within said cylinder cavity, the improvement comprising: calibration means detachably, operably coupled to said body for limiting said stroke length of said piston, said calibration means including structure within said main body defining a calibration means receiving channel communicating with said cylinder cavity;   a first calibration member operably, detachably coupled with said body and received within said channel;   a second calibration member shiftably carried within said first calibration member and extending into said channel; and   a calibration mechanism end fitting shiftably carried within said channel for sealing said piston cavity and said channel in fluid tight relationship, said end fitting including a first abutment portion for operable abutment of said end fitting with said second calibration member for positioning said end fitting within said body, a piston abutment portion for operable, stroke limiting abutment with said piston, and retaining means operably engageable with said body for retaining said end fitting within said body when said first and second calibration members are detached from said body.     
     
     
       5. The invention as claimed in claim 4, said channel defining a channel diameter, said end fitting retaining means comprising a second abutment surface received within said cavity and having a second abutment surface diameter greater than said channel diameter.